The invention relates to a device for transmitting a torque between an internal combustion engine and a generator of a vehicle.
Various solutions are known for connecting an internal combustion engine to an electric generator in a vehicle to create a range extender. For example, a shaft can be provided between the internal combustion engine and the generator, which shaft transmits the torque from the motor to the generator by means of two shaft/hub connections. To this end, on one hand, a shaft/hub connection to the crankshaft of the motor and, on the other hand, a shaft/hub connection to the input shaft of the generator are required.
Shaft/hub connections are, however, highly subject to wear, as a result of which the lifespan of the individual parts is significantly reduced. A large degree of wear occurs in particular if the crankshaft of the motor and the input shaft of the generator are not perfectly flush with one another.
The object of the invention is to provide a device which can, in a simple manner, transmit a torque from the motor to the generator and has a low degree of wear for this purpose.
The object is achieved by a device for transmitting a torque between an internal combustion engine and a generator, with a motor-side shaft, a generator-side shaft, a separate transmission element for transmitting the torque between both shafts and a seal device. The motor-side shaft and the generator-side shaft are arranged in each case substantially coaxially in relation to one another and are connected in each case via a shaft/hub connection to the transmission element. The seal device seals off to the outside a lubricant chamber which lies radially outside the transmission element, between the motor-side shaft and the generator-side shaft and which couples the two shaft/hub connections in terms of lubricant flow. As a result of the invention, it is possible to arrange both the shaft/hub connection between the motor and the transmission element and also the shaft/hub connection between the transmission element and the generator-side shaft in a joint lubricant chamber, as a result of which an effective lubrication of the shaft/hub connections and thus a significant reduction in wear are enabled. In contrast to two separate lubricant chambers for, in each case, one of the shaft/hub connections, a significant simplification and thus cost savings are provided by the invention.
At least one lubricant intake is preferably provided in one of the two shafts, in particular in the motor-side shaft. As a result, a simple filling of the lubricant chamber with lubricant is enabled.
For example, the lubricant chamber is connected to the lubricant circuit of the internal combustion engine in terms of flow engineering, as a result of which the device is much easier to realize since use can be made of the existing lubricant circuit of the internal combustion engine.
In one embodiment of the invention, the seal device has at least one seal element which, at at least one axial end, overlaps with an, in particular, tubular seal extension on one of the shafts and bears against this seal extension so that a reliable sealing off of the lubricant chamber is enabled.
For example, the seal element has an axial end with a conical seal surface with which it overlaps with the seal extension, wherein the seal extension has a complementary, conical counter-surface which contacts the seal surface. The sealing action of the sealing element can be further increased in this manner.
In one embodiment variant, at least on one of the two shafts an axially projecting, in particular tubular shell part is provided which extends around the transmission element and delimits the lubricant chamber radially to the outside at least in portions. A reliable and impervious delimitation of the lubricant chamber is possible as a result of the shell part.
The shell part is preferably embodied integrally with the generator-side shaft and the seal element bears radially on the inside against the shell part and is guided by it so that precise positioning of the seal element is ensured. For example, the shell part and the seal extension overlap so that the gap to be sealed off by the seal element is as small as possible.
In one configuration of the invention, the seal device has at least one seal element which is axially tensioned between the shafts. As a result, simple mounting of the device is enabled and by which an axial contact to avoid a gap between seal element and adjacent part is ensured.
In one embodiment variant, the seal device has at least one spring which is supported on one of the two shafts, in particular that shaft which does not have the seal extension. The spring pushes the seal element with a force against the other shaft. In this manner, a high level of imperviousness of the seal device is permanently ensured since the seal element is held continuously in its optimum position.
For example, the seal element is embodied as a sleeve or as an O-ring, as a result of which it is inexpensive to produce.
In one embodiment, at least one of the two shafts is embodied as a hollow shaft with a torque transmission profile, in particular a toothing, which is connected in a positive-locking manner to a complementary profile on the transmission element. As a result, the transmission of torque of the shaft/hub connection is ensured in a simple, but very reliable manner.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments lien considered in conjunction with the accompanying drawings.